This invention relates to the production of improved polyelectrolytes which are useful in the fractionation of blood and other proteinaceous substances. More particularly, this invention relates to aggregated water-insoluble, cross-linked polylectrolyte polymers having amine-imide functional groups.
Recently, there has been disclosed the production of certain polyelectrolyte polymers which are useful for a variety of protein separation systems. Thus, U.S. Pat. No. 3,554,985 describes the preparation of water-insoluble, cross-linked polyelectrolyte polymers having diloweralkylaminoloweralkylimide functional groups. These polyelectrolytes have been found to be useful in the fractionation of blood plasma and serum as described in U.S. Pat. No. 3,555,001 and for the separation of viruses from non-viral proteins as disclosed in U.S. Pat. Nos. 3,655,509 and 3,846,543. These polyelectrolyte polymers also are useful for the immunization of animals against viral diseases as seen from U.S. Pat. No. 3,651,213 and for the purification of water by the removal of contaminating bacteria and viruses as set forth in U.S. Pat. No. 3,398,092.
In U.S. Pat. No. 3,554,985, the water-insoluble, cross-linked polyelectrolytes are further described as being copolymers of an (a) unsaturated monomer of 2 to 12 carbon atoms and (b) a monomer selected from the group consisting of (1) a mixture of an unsaturated polycarboxylic acid or anhydride and an unsaturated polycarboxylic acid amine-imide, and (2) an unsaturated polycarboxylic acid amine-imide. In a typical example, the starting copolymer comprises the reaction product of styrene and maleic anhydride cross-linked with divinyl benzene (Example 1, Column 16) which is subsequently converted to the amine-imide derivative by reaction with dimethylaminopropylamine (Example 2, column 16). In other typical examples, a preformed polymer such as a copolymer of ethylene and maleic anhydride is cross-linked during the reaction with the dialkylaminoalkylamine by also employing in the reaction a predetermined amount of a difunctional compound such as ethylenediamine (column 12, lines 27-40).
Notwithstanding the favorable properties of the foregoing polyelectrolytes for their intended uses, it has been found in practice that they are difficult to handle in processing due to certain of the physical and chemical properties of the initially preformed polymer. Thus, it has been found difficult to filter the preformed polymer from the mother liquor following the initial polymerization reaction. Thick slurries of the polymer are formed which are slow to filter and give very dense filter cakes that do not break up readily. On drying, these products give a hard, lumpy material that requires excessive grinding.
While various procedures have been considered for overcoming these problems in processing of the polymer, a principal ultimate use of the polymer for protein fractionation following substitution with the functional amine-imide group dictates that the protein adsorption capacity and protein selectivity of the polymer be not substantially impaired.